Hybrid photovoltatic and photo-thermal solar panel

Abstract

A hybrid photovoltaic/photo-thermal panel has at least one photovoltaic cell mounted on and in thermally conductive communication with an evaporator, the evaporator being a single piece of thermally conductive material having a first outer surface configured for mounting photovoltaic cells thereon, an uninsulated second outer surface exposed to ambient air and the single piece of thermally conductive material having fluid flow channels formed therein configured to permit flow of refrigerant from at least one fluid inlet to at least one fluid outlet in the evaporator. Heat generated by the at least one photovoltaic cell or from the ambient energy of the surrounding air or other source of heat is absorbed by the refrigerant. The panel may be part of a system including a compressor for circulating refrigerant through the channels and a condenser for extracting heat from the refrigerant. The hybrid system has an increased coefficient of performance for utilizing full spectrum solar energy for both power and heating, plus environmental energy heating during poor or non-existent light conditions.

1 . A hybrid photovoltaic/photo-thermal panel comprising at least one photovoltaic cell mounted on and in thermally conductive communication with an evaporator, the evaporator comprising a single piece of thermally conductive material having a first outer surface configured for mounting photovoltaic cells thereon, an uninsulated second outer surface exposed to ambient air and fluid flow channels formed in the single piece of thermally conductive material configured to permit flow of refrigerant from at least one fluid inlet to at least one fluid outlet in the evaporator. 
     
     
         2 . The panel according to  claim 1 , wherein the thermally conductive material comprises aluminum or aluminum alloy. 
     
     
         3 . The panel according  claim 1 , wherein the single piece of thermally conductive material is seamless and the channels are entirely enclosed within the single piece of thermally conductive material except for at least one opening corresponding to the at least one fluid inlet and at least one other opening corresponding to the at least one fluid outlet. 
     
     
         4 . The panel according to  claim 1 , wherein the first outer surface configured for mounting photovoltaic cells is sufficiently flat that each of the photovoltaic cells is in contact with the first outer surface of the evaporator over an entire area of a back side of the photovoltaic cell. 
     
     
         5 . The panel according to  claim 1 , wherein the channels form an interconnected pattern configured to permit distribution of the refrigerant throughout the evaporator to contribute to uniform cooling of the at least one photovoltaic cell. 
     
     
         6 . The panel according to  claim 1 , wherein the at least one photovoltaic cell generates heat and is configured to transmit the heat by conduction to the piece of thermally conductive material, the piece of thermally conductive material transmitting heat by conduction to the refrigerant in the channels. 
     
     
         7 . The panel according to  claim 1 , wherein the at least one fluid inlet is configured to permit flow of liquid refrigerant into the channels in the evaporator, the channels are configured to permit vaporization of at least a portion of the liquid refrigerant in the evaporator, and the at least one fluid outlet is configured to permit flow of vaporized refrigerant and excess liquid refrigerant out of the evaporator. 
     
     
         8 . The panel according to  claim 1 , wherein the at least one photovoltaic cell comprises an array of photovoltaic wafers. 
     
     
         9 . A hybrid photovoltaic/photo-thermal system comprising:
 a panel as defined in  claim 1 ;   a compressor configured to raise a temperature and pressure of the refrigerant;   a condenser configured to receive refrigerant from the compressor and extract heat therefrom, thereby lowering the temperature of the refrigerant;   an expansion valve configured to receive refrigerant from the condenser and lower a pressure thereof; and,   and a plurality of fluid conduits configured to permit flow of the refrigerant from the at least one fluid flow outlet of the evaporator to the compressor, from the compressor to the condenser, from the condenser to the expansion valve, and from the expansion valve to the at least one fluid flow inlet of the evaporator, the compressor further configured to circulate refrigerant through the fluid conduits and the fluid flow channels.   
     
     
         10 . The system according to  claim 9 , wherein the condenser lowers temperature of the refrigerant sufficiently to condense refrigerant vapor. 
     
     
         11 . The system according to  claim 9 , wherein the compressor is powered by electricity and receives at least a portion of the electricity from a photovoltaic array. 
     
     
         12 . The system according to  claim 9 , further comprising a controller, a frost sensor configured to sense a temperature of the evaporator, a reversing valve and fluid heating conduits configured to cause the refrigerant to absorb waste heat from the compressor, the reversing valve configured to supply the waste heat from the compressor to the evaporator to prevent frost accumulation thereon. 
     
     
         13 . The system according to  claim 9 , wherein the system is configured to use the heat extracted by the condenser to heat water. 
     
     
         14 . The system according to  claim 9 , wherein the system is configured to use the heat extracted by the condenser to heat air. 
     
     
         15 . The system according to  claim 9 , wherein the system is configured to use the heat extracted by the condenser to heat both water and air. 
     
     
         16 . The system according to  claim 13 , wherein the water is for domestic hot water heating, a swimming pool or a spa. 
     
     
         17 . The system according to  claim 13 , wherein the water is for space heating or cooling. 
     
     
         18 . The system according to  claim 14 , wherein the air is for space heating, cooling, drying or waste heat dissipation. 
     
     
         19 . The system according to  claim 9 , further comprising one or more heat exchangers. 
     
     
         20 . A method of capturing solar energy comprising:
 converting solar energy into electrical energy with a photovoltaic cell mounted on and in thermally conductive communication with an evaporator, the evaporator comprising an uninsulated outer surface exposed to ambient air, the uninsulated outer surface absorbing heat; cooling the evaporator with a flow of refrigerant through channels in the evaporator, the cooling of the evaporator causing cooling of the photovoltaic cell through conduction of heat from the photovoltaic cell to the evaporator, the cooling of the evaporator causing heating of the refrigerant; and,   extracting the heat from the refrigerant in a heat exchanger to utilize the heat in a further application.